Lens-grinding apparatus



May 19, 1925. 1,538,811

, H. w. HILL LENS GRINDING APPARATUS Filed April 2, 1920 I4 24 I j /9 INVENTOR HA PRY W H I LL ATTORNEYS Patented May 19, 1925.

UNITED STATES PATENT OFFICE.

HARRY W. HILL, OF SOUTHBRIDGE, MASSACHUSETTS, ASSIGNOR T0 AMERICAN OPTI- GAL COMPANY, OF SOUTI-IBR-IDGE, MASSACHUSETTS,

CHUSETTS.

A CORPORATION OF MASSA- Lnnscninnrne APPARATUS.

Application filed April 2, 1920. Serial No. 370,724.

To all whom it may concern:

Be it known that I, HARRY W. HILL a citizen of the United States, residing at Southbridge, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Lens-Grinding Apparatus, of which the following is a specification.

This invention relates to improvements in lens grinding apparatus and has for its principal object the provision of a novel and improved construction of automatic mechanism for grinding or polishing lenses and forkeeping the lens surface suitably supplied with the abrasive fluid during the grinding operation.

A further object of the presentinvention is the provision of mechanism for this purpose which shall be simple of construction, shall be lighter than mechanism hitherto employed for similar purposes, and more efficient in its operation.

Other objects and advantages of my improved construction should be readily apparent by reference to the following specification taken in connection with the accompanying drawings, and it will be understood that any modifications in the specific details of construction shown and described may be made within the scope of the appended claim without departing from or exceeding the spirit of the invention.

Figure I is a vertical sectional view of a machine embodying the invention.

Figure II is a sectional view of the bowl and the lap mounted on the lower spindle 1.

Prior to the present invention certain attempt-s have been made in the production of lenses to render the operation substantially automatic, in that a bowl has sometimes been fastened to a rotating lower lens grinding shell and a scraper or the like employed, serving to throw the material forced outwardly by centrifugal action in toward the center where the grinding tool is located. Mechanism of this type, however, has been found to be open to certain objections due to the fact that at the outset it is necessary to supply a considerable quantity of abrasive in suspension within the bowl before the quantity is sufficient to be operated upon by the centrifugal action of the whirler and by the scraper to throw the material inward, making considerable weight on the spindle and requiring a heavily constructed machine. Secondly, this mechanism is particu' larly open to object-ion in the commercial production of lenses due to the fact that when the grinding action ceases if the bowl is not immediately cleaned the abrasive ma.

terial will settle to the bottom and harden so that if left without attention during the lunch hour for example, when the workman comes back considerable time must be expended in loosening and softening up the hardened material and the cost of production as well as the time required is thus considerably increased. 1

It is to obviate these difficulties and provide a simple, light and inexpensive mechanism which maybe readily caredfor, which will commend itself either for factory usage, where a large number of lenses are to be ground on the same tool, or for prescription work, where a single lens is to be finished 011 the tool with different grades of abrasive, that the present construction has been devised.

Inthe drawing, Figure I, there is disclosed the mechanism as comprising a lower spindle 1 driven through the medium of the pulley 2, and having mounted thereon the improved grinding tool. This grinding tool comprises the bowl 24, having a rim 25. The bowl is conical, and its threaded portion 23 is mounted on the threaded part of the spindle, and secured thereon by the lock nut 28 and the washer 29, which, as at 30, is keyed on the spindle to prevent any disarrangement of the adjusting mechanism,

through contact of the parts with the table 19 and the spindle hearing. The lock nut 28 serves to lock the bowl in vertical adjusted positions.

The inner periphery of the rim of the bowl is provided with a web 26, which fits tightly against the end 27 of the head portion, preferably constituting the laps 4 for grinding lenses 5 on the lens block 6. These lens blocks 6 are shown as rotatably mounted on the cone points 7 of the spider 8, which is in turn rotatably mounted on the pin 9 of the pitman arm or link 10. This arm is secured to the adjustable eccentric pin 11 on the driven disc 12, which as it is rotated serves to impart a reciprocating movement to the arm 10 and thusshifts the lens holders and lenses transversely of the lap 4. The Web u proved mechanism comprisi 26, adjacent Where it is integral with the rim 25, -l1as a:;groove or trough -1 l'atthe edge of the-Tape :p'rovidin'g a spaceso that the lenses in their reciprocations if of sufficient size, may move over to somewhat overhang the 'edg'eofthe lap l also providing a space "ivhi ch serves asa troug h and recepta cle for the abrasive bearing fluid. substantially triangular scraper member 16 is carried by the arm 17 hinged to the bracket 18 which rises from the table 19, the scraper extending down to "the bottom of the "trough andthus scrapin jlo'ose the abrasive materi'a'l lyingat the bottom'andfthrowingit in Wa'rd tow-ard-the centerof"the lap *4 to-kee a constant supply of abrasive "fluid 'on-lhe surfaceoftlie lap 4. I, a

"From the foregoing description it "\vii l be noted that there has been devised 'an imng'a'central lens holding or grinding member illustrated as of'convex form, having immediately adjacent the edge thereof a relatively slight abrasive receiving groove or channel and upstanding retaining rim, the abrasive frecei'v'i'ng space heing of size to require but a small amount dram-Siva to operate satisfactorily, thus lessenii'fg the weight of the parts, the amount of ab 'asive required, and rendering it extremely simple to clean out all old abrasive "whena finer type is*to he used, or making it easy to break up the dried out abrasive should the maohine he brought to rest for a more or less continued period.

I claim:

A lens grinding tool including a threaded spindle,a lap portion mounted upon the upper end thereof, an abrasive receiving bowl having a central threaded opening Within its bottom for adjustably manning said boWl, a jgve'b port-ion formed -'integ'r'al with said "howl upon the interior tlfereo'i and adapted to it tightly against the faces for the "lap ortion, said "Web "portion Being curved upwardly at its "inner'edge t'o Torin an abrasive receiving grooveand ineans 'for retainingsaid bowl in an aajustd p'osition u'ponthe spindle. r a

In testimony 'w'vlierraof hav e "affiXed my signature, in presence 'of'tvv'o witness-es.

HARRY WV. HILL.

Witnesses ESTHER M. Semen, Amer. G. HASEKELL. 

